June 15
1215 – King John of England signs the Magna Carta.
1752 – Benjamin Franklin proves that lightning is electricity
1776 – Delaware votes to suspend government under the British Crown and separate officially from Pennsylvania.
1804 – New Hampshire approves the Twelfth Amendment to the United States Constitution, ratifying the document.
1836 – Arkansas is admitted as the 25th U.S. state.
1846 – The Oregon Treaty extends the border between the United States and British North America, established by the Treaty of 1818, westward to the Pacific Ocean.
1849 – James K. Polk, 11th President of the United States dies at his home in Nashville Tennessee.
1864 – Arlington National Cemetery is established when 200 acres of the Arlington estate, confiscated from Robert E. Lee are set aside as a military cemetery
1916 – President Woodrow Wilson signs a bill incorporating the Boy Scouts of America
1944 – The United States invades Saipan